fix(vitest-plugin): add tsconfig paths for vite 8 type resolution

Vite 8 removed the `main` and `types` top-level fields from its
package.json, relying entirely on the `exports` map. Since the base
tsconfig uses `moduleResolution: "node"` (TypeScript 4.9.4), the
compiler cannot resolve `import { Plugin } from "vite"` without
an explicit path mapping.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: adriencaccia

packages/vitest-plugin/tsconfig.json

@@ -3,7 +3,11 @@
   "compilerOptions": {
     "outDir": "dist",
     "rootDir": "src",
-    "typeRoots": ["node_modules/@types", "../../node_modules/@types"]
+    "baseUrl": ".",
+    "typeRoots": ["node_modules/@types", "../../node_modules/@types"],
+    "paths": {
+      "vite": ["node_modules/vite/dist/node"]
+    }
   },
   "references": [{ "path": "../core" }],
   "include": ["src/**/*.ts"]